This invention relates to a so-called surround-sound generator in a stereophonic audio reproduction system and in more particular a four-channel surround-sound generator employing a delaying circuit.
There have been made many developments in the surround-sound generation technology that gives more satisfactory stereophonic sound effect to a listener than a conventional two-channel stereophonic sound. In a conventional stereophonic sound reproducing system, there are employed two separate speakers, for example, a first speaker for outputting a first channel sound and a second speaker for outputting a second channel sound in the stereophonic system, the first speaker being disposed at left or right direction to the listener and the second speaker being disposed at the opposite direction thereto. However, since the location of the speakers is conventionally fixed at a predetermined position, the listener may be unable to enjoy a perfect stereophonic sound reproduced from the speakers depending upon his location against the speakers. To solve such a drawback, one of various prior arts for surround-sound generators has been employed with the construction as illustrated in FIG. 1, which is comprised of first and second buffers (1,2), first and second amplifiers (3,4), first- and second-channel main speakers (SPL, SPR), and first- and second-channel surround speakers (SSPL, SSPR). In this construction, the effect of surround-sound comes from arranging the first and second surround-sound speakers at a direction and location different from the first and second main speakers. However, since the construction is just a parallel connection of the first-channel main speaker SPL and surround speaker SSPL and the second-channel main speaker SPR and surround speaker SSPR, the reproduced sound in each channel speaker is substantially identical and further only the direction of sound outputting is different depending on the location of the speakers used. Consequently, more satisfactory effect of surround sound in a stereophonic audio system has been very difficult to attain to its listener.